[OTTERTOK]

Thank's once again Chad. Your talking about this one right?

http://www.eagletreesystems.com/MicroPower/micro.htm


http://www.rctoys.com/rc-products-ca...A-LOGGERS.html

[Guest]

Yep thats it! The micro temp probe and powerpanel the the best add on's, two temp probes let you check packs in multi places during a flight so you can see how your cooling is working etc.

Hope that gets you going!

[OTTERTOK]

Sure does, all I've been doing is reading about electrics on Wattflyer and the Giants for the past two days and it's gotten pretty intriguing. I guess I'll get my feet wet with the Ultra-RC Giles when it gets built and I will either be using a Hacker A60-20M or A60-16L that I picked up just recently in another deal.

[OTTERTOK]

Originally Posted by Bdegan

Definately good for 50cc planes. The A60's anyway.
My Giant Reactor is 18 lbs and 86 inch wing span.

The batteries are from Hobby King. Last fall ( 2 months ago ) I paid $59 each
They are 6S 5000 Mah 20c
http://www.hobbyking.com/hobbyking/s...idProduct=9176
the new 25c's have come out now. they are $55 at the moment. and my 20c's have droped to $55 each.
http://www.hobbyking.com/hobbyking/s...idProduct=9180
Don't be afraid that these are not good batteries. Ben and BoneDoc from 3D Hobby Shop only use these batteries now, as do a lot of others. They are proving themselves to be very good batteries.

What would be the life span of these LiPo batteries, can they sit on the shelf for months or is there a certain maintenance schedule? Have you thought about going to A123 batteries?

[Bdegan]

Originally Posted by OTTERTOK

What would be the life span of these LiPo batteries, can they sit on the shelf for months or is there a certain maintenance schedule? Have you thought about going to A123 batteries?

Some guys say 100 to 200 cycles, some say more. I have seen guys using the same packs for 3 seasons easily.
I figure it all depends on how hard you tax the batteries in use.

Shelf life is a long time.

A123's are nice but I would need to run a 12S2P to get 4600 Mah in the Big Reactor. Thats 24 cells. I think that would end up heavier than my LiPo set up.

Don't know for sure, anyone have any idea how much a 6S2P A123 pack would weigh compared to a 6S 5000mah Lipo ???



Never pay again for live sex! | Hot girls doing naughty stuff for free! | Chat for free!

[OTTERTOK]

They are heavy by around twice the weight your right. I guess we'll have to wait for that technology to catch up. So if I bought some for a good deal and stored them properly they would still be good in 2 years.

[Guest]

Originally Posted by OTTERTOK

What would be the life span of these LiPo batteries, can they sit on the shelf for months or is there a certain maintenance schedule? Have you thought about going to A123 batteries?

Do not let them sit around, they suffer big time, buy em and use em. My experience (I have had probably over 50 10s lipos over the last 5 years, maybe more) is that they usually die early in the 3rd season no matter how many cycles.

Cycle life is very dependent on treatment, I have had packs die in 25 cycles, but I have never had one go more than 150 since mine have usually either been replaced with new tech by then or died of old age.

In F3A after about 100 flights performance starts to noticeably drop and the packs are only good for practice. I generally will only compete with packs that have between 25-80 cycles on them, and keep the rest for practice. You need a few cycles on them to get max performance and to make sure there is not a defect in the cells.

A123's are dramatically heavier, I don't think 12s A123 compares fairly to the newest Lipo's, maybe 13s is closer.

Remember, the higher the power application, generally the less margin you have to work with, therefore the more noticeable any loss in performance will be.

ie: if your parkflyer application only drains the pack 50% for a 10 minute flight, you can eat a 30-40% reduction in capacity from age before you will really see it. If your 3 kW application needs 80% of the battery to get a 10 minute flight, a loss of only 5% will start to show up. There lies the rub of big electrics, and why you see park flyers going hundreds of cycles.

Also don't get more than 20C for aerobatics, you don't need more power than that and lower C provides better flight characteristics.

[OTTERTOK]

Beauty, Thanks again Chad wisdom is great for us less wise to learn from.

[Bdegan]

Originally Posted by can773

Also don't get more than 20C for aerobatics, you don't need more power than that and lower C provides better flight characteristics.

Thats right, No more than 20c is needed for aerobatics and 3D type stuff.

The guys at our field that fly EDF's notice the difference from 25 to 35c .
But their systems, are turning stupid rpm's LOL



Never pay again for live sex! | Hot girls doing naughty stuff for free! | Chat for free!

[Guest]

Ya EDF is a good place for high C, I just got some of the Pro Power 45C packs for my 70mm setup. I also tried some of the new 325's 45C pro powers for indoor, they work better than the 20C I find just because of a wee better voltage retention.

For F3A I have tried high C packs, but my experience is that they let go of their power so easily that you abuse it and end up with shorter run times, and in windy conditions its easy to eat up a batt pretty quick.

For aerobatics we really want high energy density (Wh/kg), this is not affected by C rating, and since higher C packs are usually heavier they have less energy density. I think one of the highest energy density packs ever made were the 2000 mAh Prolite cells.